Hepatokines as a Link between Obesity and Cardiovascular Diseases

Hepatokines: linking nonalcoholic fatty liver disease and insulin resistance

Hepatic steatosis is an underlying feature of nonalcoholic fatty liver disease (NAFLD), which is the most common form of liver disease and is present in up to ∼70% of individuals who are overweight. NAFLD is also associated with hypertriglyceridaemia and low levels of HDL, glucose intolerance, insulin resistance and type 2 diabetes mellitus. Hepatic steatosis is a strong predictor of the development of insulin resistance and often precedes the onset of other known mediators of insulin resistance. This sequence of events suggests that hepatic steatosis has a causal role in the development of insulin resistance in other tissues, such as skeletal muscle. Hepatokines are proteins that are secreted by hepatocytes, and many hepatokines have been linked to the induction of metabolic dysfunction, including fetuin A, fetuin B, retinol-binding protein 4 (RBP4) and selenoprotein P. In this Review, we describe the factors that influence the development of hepatic steatosis, provide evidence of strong links between hepatic steatosis and insulin resistance in non-hepatic tissues, and discuss recent advances in our understanding of how steatosis alters hepatokine secretion to influence metabolic phenotypes through inter-organ communication.

T2DiACoD: A Gene Atlas of Type 2 Diabetes Mellitus Associated Complex Disorders

We performed integrative analysis of genes associated with type 2 Diabetes Mellitus (T2DM) associated complications by automated text mining with manual curation and also gene expression analysis from Gene Expression Omnibus. They were analysed for pathogenic or protective role, trends, interaction with risk factors, Gene Ontology enrichment and tissue wise differential expression. The database T2DiACoD houses 650 genes, and 34 microRNAs associated with T2DM complications. Seven genes AGER, TNFRSF11B, CRK, PON1, ADIPOQ, CRP and NOS3 are associated with all 5 complications. Several genes are studied in multiple years in all complications with high proportion in cardiovascular (75.8%) and atherosclerosis (51.3%). T2DM Patients' skeletal muscle tissues showed high fold change in differentially expressed genes. Among the differentially expressed genes, VEGFA is associated with several complications of T2DM. A few genes ACE2, ADCYAP1, HDAC4, NCF1, NFE2L2, OSM, SMAD1, TGFB1, BDNF, SYVN1, TXNIP, CD36, CYP2J2, NLRP3 with details of protective role are catalogued. Obesity is clearly a dominant risk factor interacting with the genes of T2DM complications followed by inflammation, diet and stress to variable extents. This information emerging from the integrative approach used in this work could benefit further therapeutic approaches. The T2DiACoD is available at www.http://t2diacod.igib.res.in/ .

The fatty liver index as a predictor of incident chronic kidney disease in a 10-year prospective cohort study

Background

Although non-alcoholic fatty liver disease (NAFLD) is considered to be associated with chronic kidney disease (CKD), long-term follow up data is lacking. We investigated whether NAFLD, as determined by the fatty liver index (FLI), could predict incident CKD in 10-year prospective cohort study. We also assessed the clinical utility of FLI to predict the development of CKD.

Methods

6,238 adults aged 40 to 69 years without baseline CKD from the Ansan—Ansung cohort were examined. Patients were classified according to FLI as follows: FLI<30, no NAFLD; FLI≥60, NAFLD; and 30≤ FLI<60, intermediate. Incident CKD was defined as estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m². The clinical utility of FLI in predicting incident CKD was estimated via area under the receiver-operating characteristic curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI) analyses.

Results

During an average of 10 years of follow-up, 724 subjects (15.21%) developed CKD. The adjusted hazard ratio [95% confidence interval (CI)] for incident CKD increased in a graded manner with FLI increased (<30 vs. 30–59 vs. ≥60 = 1 vs. 1.17 [0.997–1.375] vs. 1.459 [1.189–1.791], respectively, P for trend = 0.0012). Incorporation of FLI into traditional risk factors of CKD significantly increased prediction of incident CKD based on NRI (17%; 95% CI, 8.9–25%; P-value <0.001) and IDI (0.002; 95% CI, 0.0046–0.0143; P-value = 0.046).

Conclusions

FLI, a surrogate marker of NAFLD, was an independent risk factor for incident CKD. FLI provides meaningful incremental risk reclassification beyond that of conventional risk factors of CKD.

Association of leukocyte cell-derived chemotaxin 2 (LECT2) with NAFLD, metabolic syndrome, and atherosclerosis

Objective

Previous studies have shown that leukocyte cell-derived chemotaxin 2 (LECT2), a recently discovered hepatokine, is associated with the inflammatory response and insulin resistance. We examined circulating plasma LECT2 levels in the subjects with non-alcoholic fatty liver disease (NAFLD) or metabolic syndrome.

Methods

We analyzed plasma LECT2 levels from the subjects of age- and sex-matched 320 adults with or without NAFLD who completed a health check-up at the Health Promotion Center of Korea University Guro Hospital.

Results

Individuals with NAFLD showed significantly higher LECT2 levels (31.2 [20.9, 41.5] vs. 24.5[16.3, 32.7] ng/ml, P <0.001) as well as components of MetS compared to those without NAFLD. Furthermore, circulating LECT2 concentrations were greater in subjects with MetS (32.6 [17.8, 45.0] vs. 27.0 [18.7, 33.7] ng/ml, P = 0.016) and were associated with anthropometric measures of obesity, lipid profiles, high sensitivity C-reactive protein (hsCRP) and liver aminotransferase levels. However, there was no significant relationship between LECT2 levels and indicators of subclinical atherosclerosis, such as carotid intima-media thickness (CIMT) and brachial ankle pulse wave velocity (baPWV). Multivariate analysis demonstrated a progressively increasing trend of odds ratios for NAFLD according to quartiles of LECT2 levels after adjusting for risk factors, although the relationship was attenuated after further adjustment for waist circumference and lipid levels.

Conclusion

Circulating LECT2 concentrations were increased in individuals with NAFLD and those with MetS, but not in those with atherosclerosis. The relationship between LECT2 and both NAFLD and MetS might be mediated by its association with abdominal obesity and lipid metabolism.

Trial registration

Clinicaltrials.gov NCT01594710

Dietary fatty acids influence sperm quality and function

Recently, obesity has been linked to male infertility. In animal models the administration of a high-fat diet caused a reduction in sperm quality, by impairing gamete energy metabolism. The aim of this study was to investigate a possible effect of dietary fatty acids supplementation in the modulation of sperm energy metabolism and, in turn, in the improvement of sperm quality in rats fed a high-fat diet. Sexually mature male Sprague-Dawley rats were divided into four groups and fed for 4 weeks a standard diet (control group), a high-fat diet (enriched in 35% of fat and 15% sucrose), a high-fat diet supplemented with 2.5% olive oil (a source of monounsaturated fatty acids) or a high-fat diet supplemented with 2.5% krill oil (a source of n-3 polyunsaturated fatty acids). Liver and adipose tissue weight, plasma glucose, insulin and lipid concentrations were determined. Activities of enzymes involved in sperm energetic metabolism were evaluated by spectrophotometric assays. Sperm mitochondrial respiratory efficiency was also assayed. The obtained results suggest that olive oil partially counteracts the negative effects of a high-fat diet on sperm quality, by increasing gamete motility, by reducing oxidative stress and slightly improving mitochondrial respiration efficiency. On the other hand, krill oil determines an increase in sperm concentration and motility, an increase in the activities of lactate dehydrogenase, Krebs cycle enzymes and respiratory chain complexes; a parallel increase in the cellular levels of ATP and a reduction in oxidative damage were also observed. These results suggest that dietary fatty acids are able to positively influence sperm quality and function.

Obesity is more closely related with hepatic steatosis and fibrosis measured by transient elastography than metabolic health status

OBJECTIVE

The pathogenesis of non-alcoholic fatty liver disease (NAFLD) involves multiple concomitant events induced by obesity and metabolic health condition. This study aimed to assess the risk of NAFLD according to metabolic health and obesity status using transient elastography (TE).

MATERIALS AND METHODS

A total of 2198 asymptomatic adults without chronic liver disease and who underwent a medical health check-up were recruited. Subjects were categorized into four groups according to metabolic health and obesity statuses: metabolically healthy non-obese (MHNO); metabolically unhealthy non-obese (MUNO); metabolically healthy obese (MHO); and metabolically unhealthy obese (MUO). Hepatic steatosis was defined as controlled attenuation parameter (CAP)≥238dB/m, and significant liver fibrosis was defined as liver stiffness measurement (LSM) >7.0kPa, as defined by TE.

RESULTS

Compared with MHNO group, the odds ratios (ORs) [95% confidence interval (CI)] for hepatic steatosis were 2.94 [2.32-3.71], 4.62 [3.52-6.07], and 12.02 [9.08-15.92] in the MUNO, MHO, and MUO groups, respectively (P<0.001) in crude model. Regarding liver fibrosis, there was no significant difference in the ORs in MUNO group (ORs: 0.95 [95% CI, 0.33-2.78], P value = 0.929), whereas there was a significant increase in the ORs in MHO group compared with MHNO group (ORs: 4.32 [95% CI, 1.73-10.76], P=0.002) in the fully adjusted model.

CONCLUSION

Our results show that MHO was associated with both liver steatosis and fibrosis assessed by transient elastography. Our results suggest that a healthy metabolic profile does not protect obese adults from hepatic steatosis or fibrosis, indicating that obesity itself might contribute to liver fibrosis.

Lobeglitazone, a Novel Thiazolidinedione, Improves Non-Alcoholic Fatty Liver Disease in Type 2 Diabetes: Its Efficacy and Predictive Factors Related to Responsiveness

Despite the rapidly increasing prevalence of non-alcoholic fatty liver disease (NAFLD) in type 2 diabetes (T2D), few treatment modalities are currently available. We investigated the hepatic effects of the novel thiazolidinedione (TZDs), lobeglitazone (Duvie) in T2D patients with NAFLD. We recruited drug-naïve or metformin-treated T2D patients with NAFLD to conduct a multicenter, prospective, open-label, exploratory clinical trial. Transient liver elastography (Fibroscan®; Echosens, Paris, France) with controlled attenuation parameter (CAP) was used to non-invasively quantify hepatic fat contents. Fifty patients with CAP values above 250 dB/m were treated once daily with 0.5 mg lobeglitazone for 24 weeks. The primary endpoint was a decline in CAP values, and secondary endpoints included changes in components of glycemic, lipid, and liver profiles. Lobeglitazone-treated patients showed significantly decreased CAP values (313.4 dB/m at baseline vs. 297.8 dB/m at 24 weeks; P = 0.016), regardless of glycemic control. Lobeglitazone improved HbA(1C) values (7.41% [57.5 mM] vs. 6.56% [48.2 mM]; P < 0.001), as well as the lipid and liver profiles of the treated patients. Moreover, multivariable linear regression analysis showed that hepatic fat reduction by lobeglitazone was independently associated with baseline values of CAP, liver stiffness, and liver enzymes, and metformin use. Lobeglitazone treatment reduced intrahepatic fat content, as assessed by transient liver elastography, and improved glycemic, liver, and lipid profiles in T2D patients with NAFLD. Further randomized controlled trials using liver histology as an end point are necessary to evaluate the efficacy of lobeglitazone for NAFLD treatment.

Statins Increase Mitochondrial and Peroxisomal Fatty Acid Oxidation in the Liver and Prevent Non-Alcoholic Steatohepatitis in Mice

BACKGROUND

Non-alcoholic fatty liver disease is the most common form of chronic liver disease in industrialized countries. Recent studies have highlighted the association between peroxisomal dysfunction and hepatic steatosis. Peroxisomes are intracellular organelles that contribute to several crucial metabolic processes, such as facilitation of mitochondrial fatty acid oxidation (FAO) and removal of reactive oxygen species through catalase or plasmalogen synthesis. Statins are known to prevent hepatic steatosis and non-alcoholic steatohepatitis (NASH), but underlying mechanisms of this prevention are largely unknown.

METHODS

Seven-week-old C57BL/6J mice were given normal chow or a methionine- and choline-deficient diet (MCDD) with or without various statins, fluvastatin, pravastatin, simvastatin, atorvastatin, and rosuvastatin (15 mg/kg/day), for 6 weeks. Histological lesions were analyzed by grading and staging systems of NASH. We also measured mitochondrial and peroxisomal FAO in the liver.

RESULTS

Statin treatment prevented the development of MCDD-induced NASH. Both steatosis and inflammation or fibrosis grades were significantly improved by statins compared with MCDD-fed mice. Gene expression levels of peroxisomal proliferator-activated receptor α (PPARα) were decreased by MCDD and recovered by statin treatment. MCDD-induced suppression of mitochondrial and peroxisomal FAO was restored by statins. Each statin's effect on increasing FAO and improving NASH was independent on its effect of decreasing cholesterol levels.

CONCLUSION

Statins prevented NASH and increased mitochondrial and peroxisomal FAO via induction of PPARα. The ability to increase hepatic FAO is likely the major determinant of NASH prevention by statins. Improvement of peroxisomal function by statins may contribute to the prevention of NASH.

Extrahepatic Complications of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is an important cause of liver disease that is often associated with the metabolic syndrome. There is a growing awareness that extrahepatic complications occur in individuals with NAFLD, especially an increased risk of cardiovascular disease. Development of diabetes mellitus, chronic kidney disease, colorectal cancer, and endocrinopathies has been linked to NAFLD. This article reviews the extrahepatic complications affecting individuals with NAFLD and the pathogenesis underlying their development.

Pathogenesis of nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a severe form of nonalcoholic fatty liver disease and a risk factor for cirrhosis and hepatocellular carcinoma. The pathological features of NASH include steatosis, hepatocyte injury, inflammation, and various degrees of fibrosis. Steatosis reflects disordered lipid metabolism. Insulin resistance and excessive fatty acid influx to the liver are two important contributing factors. Steatosis is also likely associated with lipotoxicity and cellular stresses such as oxidative stress and endoplasmic reticulum stress, which result in hepatocyte injury. Inflammation and fibrosis are frequently triggered by various signals such as proinflammatory cytokines and chemokines, released by injuried hepatocytes and activated Kupffer cells. Although much progress has been made, the pathogenesis of NASH is not fully elucidated. The purpose of this review is to discuss the current understanding of NASH pathogenesis, mainly focusing on factors contributing to steatosis, hepatocyte injury, inflammation, and fibrosis.

Hormetic and regulatory effects of lipid peroxidation mediators in pancreatic beta cells

Nutrient sensing mechanisms of carbohydrates, amino acids and lipids operate distinct pathways that are essential for the adaptation to varying metabolic conditions. The role of nutrient-induced biosynthesis of hormones is paramount for attaining metabolic homeostasis in the organism. Nutrient overload attenuate key metabolic cellular functions and interfere with hormonal-regulated inter- and intra-organ communication, which may ultimately lead to metabolic derangements. Hyperglycemia and high levels of saturated free fatty acids induce excessive production of oxygen free radicals in tissues and cells. This phenomenon, which is accentuated in both type-1 and type-2 diabetic patients, has been associated with the development of impaired glucose tolerance and the etiology of peripheral complications. However, low levels of the same free radicals also induce hormetic responses that protect cells against deleterious effects of the same radicals. Of interest is the role of hydroxyl radicals in initiating peroxidation of polyunsaturated fatty acids (PUFA) and generation of α,β-unsaturated reactive 4-hydroxyalkenals that avidly form covalent adducts with nucleophilic moieties in proteins, phospholipids and nucleic acids. Numerous studies have linked the lipid peroxidation product 4-hydroxy-2E-nonenal (4-HNE) to different pathological and cytotoxic processes. Similarly, two other members of the family, 4-hydroxyl-2E-hexenal (4-HHE) and 4-hydroxy-2E,6Z-dodecadienal (4-HDDE), have also been identified as potential cytotoxic agents. It has been suggested that 4-HNE-induced modifications in macromolecules in cells may alter their cellular functions and modify signaling properties. Yet, it has also been acknowledged that these bioactive aldehydes also function as signaling molecules that directly modify cell functions in a hormetic fashion to enable cells adapt to various stressful stimuli. Recent studies have shown that 4-HNE and 4-HDDE, which activate peroxisome proliferator-activated receptor δ (PPARδ) in vascular endothelial cells and insulin secreting beta cells, promote such adaptive responses to ameliorate detrimental effects of high glucose and diabetes-like conditions. In addition, due to the electrophilic nature of these reactive aldehydes they form covalent adducts with electronegative moieties in proteins, phosphatidylethanolamine and nucleotides. Normally these non-enzymatic modifications are maintained below the cytotoxic range due to efficient cellular neutralization processes of 4-hydroxyalkenals. The major neutralizing enzymes include fatty aldehyde dehydrogenase (FALDH), aldose reductase (AR) and alcohol dehydrogenase (ADH), which transform the aldehyde to the corresponding carboxylic acid or alcohols, respectively, or by biding to the thiol group in glutathione (GSH) by the action of glutathione-S-transferase (GST). This review describes the hormetic and cytotoxic roles of oxygen free radicals and 4-hydroxyalkenals in beta cells exposed to nutritional challenges and the cellular mechanisms they employ to maintain their level at functional range below the cytotoxic threshold.

The Impact of Organokines on Insulin Resistance, Inflammation, and Atherosclerosis

Immoderate energy intake, a sedentary lifestyle, and aging have contributed to the increased prevalence of obesity, sarcopenia, metabolic syndrome, type 2 diabetes, and cardiovascular disease. There is an urgent need for the development of novel pharmacological interventions that can target excessive fat accumulation and decreased muscle mass and/or strength. Adipokines, bioactive molecules derived from adipose tissue, are involved in the regulation of appetite and satiety, inflammation, energy expenditure, insulin resistance and secretion, glucose and lipid metabolism, and atherosclerosis. Recently, there is emerging evidence that skeletal muscle and the liver also function as endocrine organs that secrete myokines and hepatokines, respectively. Novel discoveries and research into these organokines (adipokines, myokines, and hepatokines) may lead to the development of promising biomarkers and therapeutics for cardiometabolic disease. In this review, I summarize recent data on these organokines and focus on the role of adipokines, myokines, and hepatokines in the regulation of insulin resistance, inflammation, and atherosclerosis.

Sirtuin 3 (SIRT3) Regulates α-Smooth Muscle Actin (α-SMA) Production through the Succinate Dehydrogenase-G Protein-coupled Receptor 91 (GPR91) Pathway in Hepatic Stellate Cells

Sirtuin 3 (SIRT3) is an NAD(+)-dependent protein deacetylase. Recent studies have shown that SIRT3 expression is decreased in nonalcoholic fatty liver disease (NAFLD). Moreover, SIRT3 is a key regulator of succinate dehydrogenase (SDH), which catalyzes the oxidation of succinate to fumarate. Increased succinate concentrations and the specific G protein-coupled receptor 91 (GPR91) are involved in the activation of hepatic stellate cells (HSCs). In this study, we aimed to establish whether SIRT3 regulated the SDH activity, succinate, and GPR91 expression in HSCs and an animal model of NAFLD. Our goal was also to determine whether succinate released from hepatocytes regulated HSC activation. Inhibiting SIRT3 using SIRT3 siRNA exacerbated HSC activation via the SDH-succinate-GPR91 pathway, and SIRT3 overexpression or honokiol treatment attenuated HSC activation in vitro In isolated liver and HSCs from methionine- and choline-deficient (MCD) diet-induced NAFLD, the expression of SIRT3 and SDH activity was decreased, and the succinate concentrations and GPR91 expression were increased. Moreover, we found that GPR91 knockdown or resveratrol treatment improved the steatosis in MCD diet-fed mice. This investigation revealed a novel mechanism of the SIRT3-SDH-GPR91 cascade in MCD diet-induced HSC activation in NAFLD. These findings highlight the biological significance of novel strategies aimed at targeting SIRT3 and GPR91 in HSCs with the goal of improving NAFLD treatment.

The ratio of skeletal muscle mass to visceral fat area is a main determinant linking circulating irisin to metabolic phenotype

Background

The aims of this study were to investigate whether circulating irisin is associated with favorable metabolic parameters and how the association differs according to body composition in humans.

Methods

A total of 424 subjects (233 men and 191 women), aged 23–73 years (mean age 47.1 years), were enrolled from the Seoul Metro City Diabetes Prevention Program. Body composition was determined using an impedance body composition analyzer, and serum irisin level was measured using a commercial kit.

Results

Serum irisin was correlated with favorable metabolic parameters including less obese, lower blood pressure and glucose levels and healthy lipid parameters. The skeletal muscle mass to visceral fat area ratio (SVR) was positively correlated with the serum irisin concentration (r = 0.10, P = 0.04). When the study subjects were divided into tertiles according to their SVR, serum irisin was correlated with favorable metabolic phenotypes in those subjects in the upper tertile. However, there were no such correlations in the lower tertile. In addition, serum irisin was inversely related to pre-diabetes/type 2 diabetes (T2D) independent of other risk factor for T2D and insulin resistance [OR (95 % CI); 0.66 (0.49–0.90), P = 0.009].

Conclusions

The compositions of skeletal muscle and visceral fat play key roles in the association between circulating irisin and a patient’s metabolic phenotype.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-015-0319-8) contains supplementary material, which is available to authorized users.

Metformin Restores Parkin-Mediated Mitophagy, Suppressed by Cytosolic p53

Metformin is known to alleviate hepatosteatosis by inducing 5’ adenosine monophosphate (AMP)-kinase-independent, sirtuin 1 (SIRT1)-mediated autophagy. Dysfunctional mitophagy in response to glucolipotoxicities might play an important role in hepatosteatosis. Here, we investigated the mechanism by which metformin induces mitophagy through restoration of the suppressed Parkin-mediated mitophagy. To this end, our ob/ob mice were divided into three groups: (1) ad libitum feeding of a standard chow diet; (2) intraperitoneal injections of metformin 300 mg/kg; and (3) 3 g/day caloric restriction (CR). HepG2 cells were treated with palmitate (PA) plus high glucose in the absence or presence of metformin. We detected enhanced mitophagy in ob/ob mice treated with metformin or CR, whereas mitochondrial spheroids were observed in mice fed ad libitum. Metabolically stressed ob/ob mice and PA-treated HepG2 cells showed an increase in expression of endoplasmic reticulum (ER) stress markers and cytosolic p53. Cytosolic p53 inhibited mitophagy by disturbing the mitochondrial translocation of Parkin, as demonstrated by immunoprecipitation. However, metformin decreased ER stress and p53 expression, resulting in induction of Parkin-mediated mitophagy. Furthermore, pifithrin-α, a specific inhibitor of p53, increased mitochondrial incorporation into autophagosomes. Taken together, these results indicate that metformin treatment facilitates Parkin-mediated mitophagy rather than mitochondrial spheroid formation by decreasing the inhibitory interaction with cytosolic p53 and increasing degradation of mitofusins.

A Prospective Study of Fatty Liver Index and Incident Hypertension: The KoGES-ARIRANG Study

Background

Although non-alcoholic fatty liver disease is the hepatic manifestation of metabolic syndrome, its influence on hypertension development is poorly understood. We investigated whether fatty liver disease, as assessed by the fatty liver index, could predict the development of hypertension independently of systemic insulin resistance, inflammatory status and adipokine levels.

Methods

Prospective cohort study of 1,521 adults (484 men and 1037 women) aged 40 to 70 years without baseline hypertension examined. An equation was used to calculate fatty liver index and classify patients as follows: fatty liver index <30, no non-alcoholic fatty liver disease; fatty liver index ≥60, non-alcoholic fatty liver disease; and 30≤ fatty liver index <60, intermediate fatty liver index.

Results

During an average of 2.6 years of follow-up, 153 subjects (10.06%) developed hypertension. Fatty liver index was positively associated with baseline blood pressure, homeostasis model assessment of insulin resistance, urinary albumin/creatinine excretion, and high sensitivity C-reactive protein. After adjustment for confounding factors, including markers of insulin resistance, systemic inflammation and adiponectin levels, the odds ratio [95% confidence interval] for the incident hypertension increased in a graded manner with fatty liver index (<30 vs. 30–59 vs. ≥60 = 1 vs. 1.83 [1.16~2.88] vs. 2.09 [1.08~4.055], respectively).

Conclusions

Non-alcoholic fatty liver disease assessed by fatty liver index was an independent risk factor for hypertension. Our findings suggest that fatty liver index, a simple surrogate indicator of fatty liver disease, might be useful for identifying subjects at high risk for incident hypertension in clinical practice.

Endocrine causes of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the industrialized world. The prevalence of NAFLD is increasing, becoming a substantial public health burden. NAFLD includes a broad spectrum of disorders, from simple conditions such as steatosis to severe manifestations such as fibrosis and cirrhosis. The relationship of NAFLD with metabolic alterations such as type 2 diabetes is well described and related to insulin resistance, with NAFLD being recognized as the hepatic manifestation of metabolic syndrome. However, NAFLD may also coincide with endocrine diseases such as polycystic ovary syndrome, hypothyroidism, growth hormone deficiency or hypercortisolism. It is therefore essential to remember, when discovering altered liver enzymes or hepatic steatosis on radiological exams, that endocrine diseases can cause NAFLD. Indeed, the overall prognosis of NAFLD may be modified by treatment of the underlying endocrine pathology. In this review, we will discuss endocrine diseases that can cause NALFD. Underlying pathophysiological mechanisms will be presented and specific treatments will be reviewed.

Use of a Diabetes Self-Assessment Score to Predict Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are strongly associated with obesity, insulin resistance, and type 2 diabetes. We recently developed and validated a self-assessment score in the Korean population to identify people at high risk for diabetes. The objective of this study was to evaluate whether the self-assessment risk score for diabetes can also be used to screen for the presence of NAFLD or NASH.The study population included 15,676 subjects (8313 men and 7363 women) over 20 years old who visited the National Health Insurance Service Ilsan Hospital in Korea between 2008 and 2010. Anthropometric, clinical, and laboratory data were analyzed during regular health checkups. Fatty liver disease was diagnosed using ultrasound, discrimination capability was assessed based on the area under the receiver operating characteristic curve (AUC), and evaluation measures, including sensitivity and specificity, were calculated. Multiple logistic analyses were also performed.We calculated a self-assessed risk score for diabetes (range: 0-11), and a cutoff of ≥5 identified 60% (50%) of men (women) at high risk for NAFLD, reflecting a sensitivity of 79% (85%), a specificity of 60% (66%), a positive predictive value (PPV) of 68% (51%), and a negative predictive value (NPV) of 73% (91%), with an AUC of 0.75 (0.82) for men (women). A cutoff point of ≥6 identified 43% (31%) of men (women) at high risk for NASH, reflecting a sensitivity of 80% (86%), a specificity of 64% (75%), a PPV of 30% (28%), and a NPV of 94% (98%), with an AUC of 0.77 (0.86) for men (women). The odds ratios that a 1-point increase in the diabetes risk scores would be associated with an increased risk for NAFLD and NASH were 1.20 [95% confidence interval (CI): 1.16-1.25] and 1.57 (95% CI: 1.49-1.65), respectively, in men, and 1.28 (95% CI: 1.21-1.34) and 1.89 (95% CI: 1.73-2.07), respectively, in women.The present study indicates that our self-assessment risk score for diabetes could be an effective primary screening tool for the presence of NAFLD or NASH.